Telephone-exchange system



Feb. '19 1924..- 1,483,900

A. E. LUNDELL.

TELEPHONEEXCHANGE sYsTEM Filed Aug. 2s, 1919 5 sheets-sheet i A/benELande 1919 s sheets-smet -2' ES @n WIM A; E. LUNDI-:LL

TELPHONE lEJXCIMNGE SYSTEM 4 Filed Aug. 23,

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//7 yeh for l/Sen E L11/7de# EWI Tw Feb. 19 1924.

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Patented Feb. 19, 1924.

Unirse stares PArenrorrrce.

ALBENE. LUNDn-LL, or NEW YORK, N. Y., 'AssreNon To WESTERN annotareYcora- PANY, iNconroRAfrEn, or NEW Yon-K, N. Y.,.n conPoaA'rIoN or NEWYoan.

TELEPHONE-EXCHANGE SYSTEM.

Yapplicati@ med August 23, 1919. sel-iai No. 319,309.

To @Zlio/m it may concern v Be it known that I, ALBEN E. LIUNDELL, ,acitizen of the United States, residing'. at `New York, in the county o'lBronx, State of New York, have invented certain new and usetulImprovements in Telephone-EX- change Systems, oi which the following isa full, clear, concise,'andexact description.

This invention relates to' telephone eX- change systems, and moreparticularly to registering systems for automatic or semiautomatictelephone exchanges.

An lobject of the present invention is to Vcontrol selection of a calledline according to a system of numbering different from the system used'for designating the called line. A further object of the inventionis torovide means for convenient changes in the method of selecting calledlines without ret,-

Cil

i' and Fig. 3 (which is to be placed below erence to o-r change in theirnumerical designations.

This is accomplished by making use ot a selecting mechanism and afurther object of the inventionprovides simple and .inexpensive meansfor settingV thel selecting mecha.- nism upon the selected point. .i n

Although the annexed description and drawings show va semi-automaticsystem, it is understoodthat the scope of the invention is notdetermined by the particular structure disclosed, reference being hadVto the appended claims Vfor that purpose.

In the drawings, Fig. lrrepresents a call-- ing subscribers line, aconnecting circuit, and a selector switch; Fig. 2 (to be placed to theright of Fig. 1) a connector switch adapted to seize a calledsubscribers line;

4Fig-1') a selector controlling apparatus; and a registering apparatusby means of which the selector controlling apparatus and in turn theselector and connector switches may be set.`

The selector and sequence switches will not be disclosed in full in thefollowing description of this system, since switches ot this type Varewell-known in the art. A complete description of such switches may beobtained from Patent No. 1,168,319, patented January 18, 1916, to A. E.Lundell.

When thel calling subscriber at vstation 100 desires to obtain aconnection with'another subscriber, as, for example, station 200, heremoves his receiver from the switchhook andV closes thereby a circuitfor line relay LB, which in turn lights a calling lamp CL. The operatorupon noticing lamp GL lighted, inserts plug 101 into jack 102 in whichthe calling line terminates-where-` upon a circuit is closed fromgrounded battery, through the winding of cut-oit relay CR, sleevecontacts of jack 102 and plug 101,

and the winding ot relay 103 t-o ground.

Relay103 closes a circuitv from ground, through the armature and frontcontact of relay .103, contact104 and power magnet of sequence switch105 to ground battery. Normal spring 106 controls the movement ofsequence switch` 105 through to position 2. A circuit is now closed fromground, se-` quence switch contact 107, conductor 108, contact300 ofsequence switch 301, the l winding of rela-y 302 to grounded battery.The energization of the relay 302' closes a circuit from ground,lett-hand armature and front contact or relay 302, contact 303, and thepower ,p magnet Lot sequence switch 301 to grounded battery. Normalspring 304 controls the movement ot' sequence switch 301 throughtoposition 2. Although the energizing circuit or" relay v302 'becomesAbroken at contact 300 upon the movement ot' n sequence switch 301 out ofposition 1, relay 302 does not deenergize, a circuit for holding itenergized being closed from grounded battery, windingl of relay 302,sequence .switch contact 305, right-hand armature-and front` contact ofrelay 302, conductor 306, and contact 109 of sequence switch v105- toground. i

The operator depresses her-.listening key 110 and thereby connects hertelephone set ing subscribers line, establishing a conver- 'sationalcircuit to him and, in accordance V111 to the connecting circuit and tothe callf paratus provided for registering the numerical designation ota called subscriber.

Only two sets of register keys are shown` in the Vupper right-handcorner ot Fig. 3, as it ico is thought to be sufficient for the purposeof describing the` present invention 'to describe the setting ofinterconnectingv means 112 and connectingfmeans 201 respectively inaccorda-nce with two.` digits ofthe called subscribers number.

Itwill be2-obvious tof those skilled in thealrt that these switches or agreater number of switches maybe Vset grounded battery.

by meansot other digits et the numerical designation of the calledsubscribers line. n

It willalso be obvious to those skilled in the art that the jack-plug'connection at 102 and 101 can be replaced by Well-known line-tindingmeans and that by providing at subst-ation 100 a Well-known callingdialthe registering keys 401, 402 and 405 can bevreplaced by switches ot.the step-by-step type, thereby converting` the system from the semi tothe full automatic type. rSuch mechanically operated registers mightbeeolE the typeshoivn in the patent Yto Polinlroivsly 1,193,053, issuedAugust 1,' 1910. Y

rissun'iing that the designation of the called subscrib'crs line is suchas to ,cause the registering device 401 to be set in such aposition-there being several other positions- Y as to open Contact 403,instead of one 'of the other contacts, which are opened when the deviceis set in such other positions; and to set registering device 402 toopencontact- 404, the ope-ration ot' starting device 405 closes the'Following circuit; ground, sequence-switch contact 310, startingcontact 405, right-hand Winding ot relay 406 to lay v406 lcloses acircuit 1from.grouml, lefthand arn'iature and front contacto't relay400, conductor 407, sequence switch Contact 311, and power magnet otsequence :switch 301'to grounded battery. r1he movement jot sequenceswitch 301 from position 2 through to position 3 is controlled b ynormal spring 304. A circuitis noiv closed for up-drive magnet 408 fromgrounded battery, up-driif'e magnet 40S, sequence switchv contact P22,conductor 40T, let'tdia-nd front contact Vand armature ,of relay v400 toground. Relay 400 has remained in its operated` position by virtue oithe closure ot' the hillovving circuit: grounded battery, right-handWinding, front contact and armature ot' relay 400,co1nmu tatorsegment409v` and commutator brush 410 to ground.V Relay406 is provided with asecond winding 411 by meansot which the electrical condition ot' thetivo rovvs ot' termina-ls 412 and 413 are tested in turn as then'iovable brushes 4.15 and 414 come into contact therewith. Y

The row ot terminals `412 is arrangedY in groups, there being` as manyterminalsin' each group as there are points in the registering' device402, and as ina-ny groups as there are pointsm registering device `401.Y

The roiv of terminals 413 are also arranged in groups and thecorresponding terminals of each group are connected together. Forexample, the iirst terminals of each group are connected together and tothetirst point 416 of registeringl device 402, the sec ond terminals ofeach group are connected together and to the second point `oit regis Itering device 402Y and so on. Y It will be seen therefore,that 'therecan be provided as The energization ot remany terminalsin the translatordevice 417 device 401,'and that Contact 404 has been openel by theoperation ot registering.de`

vice 402, the upward"movement of trans-V lator 417 is stopped onlyvV1vlien brushes 414 Y and 415 contact with terminals in the secondgroin) and specifically the sixth terminal of the second group, sincethe lett-hand Winding'V ot' lrelay 400 lines a closed circuit'ivhen jthe brushes 414. andA 415 Contact with any terminals previous to thosementioned. Since the electrica-l condition set up at'the time thebrushes contact. with one ot' thesel previous sets of terminals isdierent from that set up at another previous terminal, ttor the sake olbrevity 'only tivo of theser .cases will be described in detail.,` ltmaybe readily understood thatthe other conditions are similar, vthe onlydifferences beingv in regard to the particular wiring Contact andterminal numbers. lYhen, `for example, the brushes 414 and 415 are inengagen'ientwith the tirstI termi-nal ot the tirst group,l a eircuit isclosed from ground, contact 416 of registering device "402, conductors418 and 4.19, brush-414, to the test Winding 411 ot' relay 406. Anothercircuit is closed` from ground, contact 420 of -registering device 401,conductor 421, brush 415 to relay 400. lllhen, for example, brushes414and 415 are in engagement withv thel second terminal ot the trst group,`the following,- circuit is closed: ground, contact of registoring,`device 402, conductor 423, brush 414, to test Winding 411 of relay 406.`VIt will be'seen, therefore,` that the tcstrelay 406 cannot dcenergizeuntil brushes 415 and 414 are Vinr engagement `u'itlithe open contactsof registering devices 401; and 402 respectively, and the commutatorbrush 410 reaches an insulated segment of the commutator Contact 409.

lpon the release of relay 400, the circuit ot the upedrive magnet 408 isopened, causing the brushes ol the translator device 417 to` come torest` and closing thev followingr circuit: 0'round left-hand armatureand i back contact et test relay 406, sequence switch cont-actV 318, andpower nfiagnet ofscquence Sivit-eh 301.Y The sequence switch 301 isvvmoved through .to spring 304. y. Y Y,

A fundamental circuit is vnoiv closedv from i Igrounded battery, throughwinding. of relay contact oli counting` relay O', Winding of'.

stepping relay 315, conductor'316, sequence Vsivitc i contact 116 toground. Y Relays 113 and position 4 vby normal 3l5beconie energized; YBela-y 113 closes the Van alternate path through its left-handv armatureand front Contact and the sequence switch contact 119. 'Upontheenergization of relay 315, a circuit is closed from ground, frontcontact and armaturefof relay 315, sequence switch contact 317,conductor 318, brush 424, stationary contact 425, conductor 426,conductor 42T, conductor 332, the armatuic and back Contact of the No.V9 counting relay, winding of counting relay 9, to grounded battery. Thecounting relay 9 closes a circuit trom ground, through sequence switchcontact 320, conductor 321, armature and .front contact of countingrelay- 9, winding of counting. relay 9', winding of counting relay 9 togrounded battery. Counting relay 9 cannot become energized, however,because ot a short-.circuit around its winding, there'being a directground on its armature and back contact which originated at the frontcontact of stepping relay 315 as described above. A circuit is alsoclosed for the lip-drive magnet 120 of selector 'switch 112 by way ofsequence switch contact 121 and right-handr frontvcontact and armatureof relay 113. The energization of magnet 120 attracts armature 122,

pressing brush rod 123 against the constantly'driven roller 121. Thisimparts 'an upward motion to the brush rod '123 `and drives selector'wipers 121, A125, 126, and

commutator brushes 127l andv 128 in an upward direction. lVipers 124,r`125 and 126 come into contactwith corresponding rows of stationaryterminals such as shown, andV commutator brushes 12T and 128 traversethe conducting and'insulated segments Vof connnutator plate 130. lVhenthe commutator brush 128 contacts with a conducting segment `131, groundis connected through the segment, conductor 132, sequence switchVcontact3133,.to the conductor 115, thereby short-circuiting relay 315,the'other side of the winding of which is also connected to the groundatsequence'switch spring 116.

'Relay 315 opens atits front contact the short-circuit around the No. 9counting re-v lay,permitting the energization of this relay, andconductor 332 becomes connected by way .oit the armature and frontcontact of the No. 9" counting relay to the varmature and back contactof the No; 8 counting relay. The arrangement of the No. 8 counting'relayand its mate, the No. 8 relay, .as wellvas'the remaining pairs otcounting relays is similar to that of the No. 9 and blo.`

9 counting v relays previously described. `When the coininutator brushl28leavesconducting segment 131, .relay 315 is again en ergizedi This inturn operates counting re lay 8 whichV accordingly.connectsinto cirvcuit the No. 8 counting relay but the latter cannot operate because otya short-circuit corresponding tol the one described :iforthe No. 9Yrelay previously.` In substantially the saine manner the remainder ofthe counting relay chain cooperatesv with the opening and closure oi theground at com-' muta-tor brush 128, as the brush rod` conf tinues itsupward motion over the vinsulated and conducting segments, until after i10 steps, when the 0 counting relay becomes energized. This opens thefundamental circuit, including tlie windings .of relay315 and 113, andcloses the following circuit:v ground, sequence switch contact 324,inner arma-ture and front contactl of the 0 counting relay, power magnetof sequence switch 301, to grounded battery, thereby causing themoveinent'of the sequence switchoutoiv position L1, and because of thenormal spring 304: into position 6. The duration of the opening of thesequence switch contact 320 between positions 4 and 6 is suliicient torellease all of vthe counting relays which-have been locked up in; t-heselecting operation `just described. Y

lture and back contact of relay 113, sequence switch contact, 135,conductor 118. and the power magnet ot sequence switch to' groundedbattery, t moving the sequence switch into position It will be notedthat the release of relay v113V alsoopens the circuit of the up-drivemagnet 120, thereby stopping the brushes in their displaced lposition. y

lVhen the sequence switch reaches position 6, acircuit isclosed fromground, sequence switchcontact 136, right-hand Winding of relay 138,Vtogrounded battery, for energizing relay v138.

cuit from ground, through the right-hand armature and front contact ofrelay 138, se-

quence switch Contact 140, conductor 118, V

and the power magnet ot sequence switch 105 to. grounded battery,whereupon the seL i Vquence switch moves into position 72 lf the trunkfirst reached were busy, whenI the energizing circuit orrelay138 becameyopen Aat sequence switchy Contact 136, this relay would be maintainedenergized,;becausey 0f a circuit consisting ofIthelett-handwinding-,middle front contact `and armature of this relay,conductor152 to the test contact ont the busytrunk. l e ,l

. 115,. The operation ofi-clay 138 closes afcir- The up-,driif'e'magnet120 wouldL then be switch Contact 145, up-drive magnet 120, toY

grounded battery. vWhen the wipers 124,

' 125 and 126 reach the terminals oan idle trunk, and .let us say nowthat trunk 202, 203 Yand 204 Vis the .irst .idle trunk, no groundcircuiti.V .will be aifailable for holding energized tlie'lei't-handwinding oi re- 133 so that when tliecoininutator brush. 127 engagesaninsulated segment 141 of the coniuiutator plate 130, rela-y138Ybeconies deenei'gized and opens the circuit of magnet 120.A Theupward movement of the brush rod 123 is'thcrehy arrested and the wipers124, 125 and v126 remain in engagement with 'the terminals connected totrunk conductors 202, and 204. l

The releaseof'i'elay 133 closes a circuit by way of sequence switchContact 146, conductor'118, power magnet 'ot sequence switch 105 to"grounded battery, moving the sequence switch out of position 7 and intoposition 11. Sequence switch 301 is now in position (i-as previouslydescribed, and se-V quence switch 205 is in position 1, since it wasassumed that trunk 202, 203 and 204, which terminates in the selector201 and sequence switch shown in Fig. 2 wasidle, that is in the normalposition.

A, new fundamental circuit is now closed as vfollows: groundedbattery,winding oiu relay 207, sequence switch contact 208, trunk conductor 202,wiper 124 of selector 112, sequence switch contact 150, conductor 115,sequence switch Contact 314, outer ar vmature and 'baclr contact of the0 counting yit' relay, windingoi stepping relay 315, conductor 310,sequence switch contact 151, wi per 1250ic the selector 112, trunkconductor 203, and sequence switch contact 200'to ground.

Relay 207 closes a circuit -from ground, through its right-hand armatureand front Contact. contact 210, and the power magnet of sequence switchv205 to grounded battery, and this sequence switch is thereuponii'iovedinto position 2. rlhe relay 207. locks up througlijits left-handV frontcontact andarmature and sequence switch Contact 211 independent ofcontact 208, and thus will not become deencrgized lwhenV the .sequenceswitch 205 leaves positionl and Contactr 208 becomes opened. In position2 of sequence switch 205 a circuit is closedV from ground,

through sequence switch contact 212, the winding of rela-y 20S togrounded battery, and this relay upon operating closes acircuit fromground, through its right-hand arr mature and Jfront contact, contact213 and.v the'power magnet of sequence switch 205 to grounded battery,whereupon this Sequence switch is moved into position 3. Relay 206,

although its energizing circuit is opened at continued closure' of` thefcllowingcircuit: ground, sequence switch contact 153 of Fig.VV

'1, bach ContactV and middle armaturefo't' re- Y lay 133, conductor.152,brush. 126, conductor 204, f lett-hand f yarmature and :trentvContact 'ot relay 206 of Fig. 2,- thrcugh the winding of this relay togrounded-batteryj y Y Y The upfdrive magnct215 of connector 201 is nowenergized by'way o1E a circuit originating at the right-hand yarmatureot' relay 207, right-hand t'ront contact of this relay, sequence switchContact 216, up-drive magnet 215, to grounded battery. The armature 217is' accordinglyv attracted and presses brush rod `213 against constantlydriven roller 219, thereby causing the'connector switch wipers 220.,221, 222, and cominutator brush 223 to move in an upward* direction. acontact bank in which called lines terminate, the coinniutator brush 223contacting with conducting and insulated segments, such as and 220, otthe commutator plate 227 Asa result of the energization ot' relay 315which occurred when the new fundamental circuit. including'- relay 207was closed, a circuit is Vnow closed from ground, through the frontcontact and armature ot relay 315 of Fig. 3, sequence switch contact330, conductor 331, wiper 428, terminal 429 ofntranslator 417, conductor430, conductor 431, conductor 432, armature and back contact-of- No. 3counting relay, winding Of No. 3 countingrelay to grounded battery. Thecounting relay chain under control of stepping relay 315, ope-ratesv` insubstantially the same manner as previouslyA described. Theshortcircuits for the stepping relay are caused by the closure of a4 circuitfrom ground, through Vcommutator brush 223, conducting segment 225',conductor 230, se-

quence switch cont-act 231, to the conductor 2PZ-which is, as previouslydescribed, connected through to thev stepping` relay: 315, and thecurrent from theV grounded .battery through the winding o1? relay 20.7vnow` flows .to ground at comniutator brush 223.-? After tour. impulseshave beencountedoff-(conductor 431 having beenV connected. to the No. 3pairof counting relays) the 0 counting relay opens the fundamentalVcircuit at its outer armature and when commutator brush counting relayalso closes a circuit from ground, through sequence switchV Contact `theinner armature and iront 'contact of the 0 counting relay throughthepower magnet ciC sequence switch 301 to lgrounded battery, for movingthe sequence switch out 01" position 6, which because Yof the normaspring 304 continues into position 16.;l

The wipers mentionedA traversel second section 442 of the connectingrack 443. By ymeans of this connecting rack the lnumber of impulses tobe transmitted over the fundamental circuit 115 and 316 'can be changedat will in a simple and efficient manner. v

A circuit is then -closed from ground, through sequence switch contact335, conductor 336, Contact 155 and the vpower magnet ot' sequenceswitch 105 to groundedbattery, and sequence switch 105 is accordinglymoved. out of position 11, andv because of normal spring 106 moves intoposition 16. As soon as sequence switch 105 moves out ot position11,'contact 109 Aof this sequence switch is opened and relay 302 becomesdeenergized. A circuit is thereupon closed from ground, through theleft-hand armature and back contact of relay 302, contact 337. and thepower magnet of sequence switch 301 to grounded battery for moving thissequence switch out of position 16 into `position 18. In positions 17and 18 of sequence switch 301, contact 333 closes a circuit from groundto release magnets 433, 434 and 440, through these release magnets togrounded battery,` and the energization ot the releasel magnets restoresthe associated registering` devices to normal. In position 18 otsequence switch 301 a. circuit is closed from sequence switchcontact 334toconductor 338 to the down-drive magnet 435 of the translator 417,causing' the brush rodV 436, the wipers 414,415, 424, 428, and thecominutator brushes 410 and 437 to be moved in a downward direction.IVhen cominutator brush 437 strikes conducting segf ment 433 a ,circuitis closed from ground,

commutator brush 437, conducting segment 438, conductor 439, sequenceswitch contact 337, and power magnet of sequence switch 301 to groundedbattery, moving sequence 'switch 301 outI of position 18 and into itsnormal position ,1. The opening of sequence` switch contact 334deenergizes dowii-drive magnet 435. It will be noted that the selectorcontrolling apparatus, the translator 417, and the registering devicesof Fig. 3 are now fully restored to their normal position and ready tobe used on the next call.

Upon the deenergization of relay 207 of battery for moving this sequenceswitch out ot position 3 into position 13.. After the testing of Vtheselected line in accordance with any well-known manner of testing suchlines, a ringing circuit is closed from ringing current source 234,through the Winding i ot relay-235, sequence switch Contact 236, wiper221, the called substation circuit, wiper 220l and sequence switchcontact ,23.71110 ground. Relay 235 is `marginal and does not operate`.upon the relativelysm-all current which isl permitted to flow throughVthe `condenser at Vthe called station, but upon vthe removalof thereceiver the current low is increased and the marginal relay 235 becomesoperated, thereby closing the follow? ing' circuit: ground, sequenceswitch contact238, the lfront contact and armature'ot' relay 235, thepower magnet of sequence switch 205 to groundedbattery. Sequence switch205 is moved out of position 13 and into position 16. The movement ofthesequence switch out of position 13 necessarily releases marginalrelay 235.` The calling and called subscriber are nowtelephonicallyconnected, `the. talking circuit being indicated byrelatively heavy lines in Figs. 1 and 2.

Upon completion of the conversation tlie subscribers replace theirreceivers on the switchhooks and cause in awell-known manner theactuation ot supervisory devicesl 160 and 161, .together with any localsignals `which it may be desirable to place under the control ot thesedevices. The operator upon noticing the actuation of these signalsremoves tlie plug 101 from jack 102, whereupon cut-oliij relay CRandrelay 103 areV released. In the case of a full automatic exchange, thertrain of switches including the linefinding means, lis restored. whenthe subscribers replace their receiver, in a manner well-known in theart; and accordingly relays CR and 103 are released. A circuit is thenclosed from ground, through the arma-ture and back contact of relay 103,sequence switch contact 162, the power magnet of sequence switch 105 togrounded battery, whereupon this sequence switch is moved out ofposition 16 and into position 18. Inthis last-mentioned position acircuit is closed from ground, sequence switch contact 164, downdrivemagnet 163, to grounded battery, and armature 165 upon becomingattracted causes the restoration of brush rod 123 in a downwarddirection.

Upon reaching its normal position a circuit is closed by way ofcominutator brush 127, conducting segment 167, which is closed only atthe normal position, conductor 168,'Se-

quenceswitch contact 169, conductor 118, the power magnet of sequenceswitch 105, to grounded battery,.moving this sequence switch out ofposition 18 and into norma-l position 1. IVhen the sequence switchleaves position 18 magnet 163 becomes deenergized.

Relay 206 of Fig. 2 is released as a result of the opening of sequenceswitch contact 153, which occurred when sequence switch 105 moved fromposition'l to 18. A temporary make busy circuit kis closed from ground,through se uence switch contact 240, through the le t-hand back contactand armature of relay 206 to conductor 204 i'or maintaining the busytest condition on the multiple bank terminal connected thereto duringthe period that connector switch 201 is being restored. In, consequenceofthe release of relay 206 a circuit is closed .from ground, right-handarmature and back contact ot this relay, sequence switch contact 241,power magnet of sequence switch 205 to grounded battery,

causing the movement of this sequence switch out ot' position 16 andinto position 18. This in turn closes a circuit from ground, throughsequence switch contact 242 closed in position 18, winding of downdrivemagnet 243 to grounded battery. The energization Vof down-drive magnet243 causes the restoration of connector 201 to the normal position. Thencommutator brush '223 contacts with conducting segment 244, a circuit isclosed from ground, through Vcommutator .brush 223, 'conducting segment244, conductor 245 and Contact 246 through the power magnet of sequenceswitch 205 to `grounded battery for moving this sequence switch out ofposition 18 and into its normal position 1. The opening of sequenceswitch contact 242 releases dowirdrive magnet 243 andthe opening ofcontact 240 permits the Atrunk 202, 203, 204 tofbe again seized for akbranch ot said circuit extending from stav tionary contacts of saidswitch, and means for selectively opening any one of the circuitextensions oi each branch tojointly directv the movement of said switchunder the control of said relay.

2. In a telephone exchange system, a selector switch, a control relaytherefor, a branched circuit for said relay extending to movablecontacts o'tsaid switch, a plurality ot normally closed extensions ofeach branch -of said Acircuit extending from stationary contacts of saidswitch, and means for simultaneously and selectively opening anexltension of each branch of said circuit to jointly direct the movementof said switch underthe control of said relay.

3. Ina telephone exchange system, a selector switch, a test relay forcontrolling the movement of said switch, a branchedy circuit for saidrelay extending toinovable contacts of said switch, a plurality ofextensions of said circuit extending from stationary contacts of saidswitch, and means tor selectivelyk controlling the circuit extensions ofsaid branches invarying combinations to` direct the movement of saidswitch under the control of said test relay.

4. In a telephone exchange system, a selector switch, a plurality of-test circuits ai'- raiiged in groups, means for selectively al teringthe test condition in any circuit in each of said groups, and means fortesting circuits in all of thek groups simultaneously and for advancingsaid switch toa point jointly predetermined by the test condition in thecircuits selectively altered.

5. In a telephone exchange system, a' se-` ber of branches of said testcircuit to a corresponding number ot contact devices,

and means for stopping said switch` upon reaching a resting position inwhich all branches of the test circuit are opened.

6. In a telephone exchange system, a selector switch having al pluralityof resting positions, a multiple test circuit with branches, a pluralityof normally closed contact devices tor each ot' said branches, means forsimultaneously connectingk a number ot' branches of said test circuit toa corresponding number of contact devices, means for advancing saidswitch whenever the test circuit includes one or more closed contactdevices, and means for stopping said switch upon reaching a restingposition in which all branches ot the test circuit are opened.

7. In a telephone exchange system, a selector switch having a pluralityof resting positions, a multiple test circuit with branches, a pluralityof normally closed extensions for each branch of saidy circuit, meanstor advancing said switch and for associating each ot said branches withthe extensions thereof, means for opening any ot said extensions andmeans for arresting said switch. when each branch of said Vtest circuitbecomes associated with an open ex'- tension thereof, the number o1resting positions being equal to or less in number than the product otthe number of extensions in all branches. Y

8. An electrical system tor selecting terminals comprising an apparatushavingregisters corresponding to groups ofsome numerical system, atranslator Vcontrolled by said register, a selector controllingapparatus for eiecting the selection of terminals in accordance with lanumerical group different from that first named, and means for 'alteringthe relation between said transla-l groups with said controlling means,a source v of testing potential normally connected to all of saidterminals and means comprislng registering devices for selectivelydiscon-V necting said potential from a terminal of 'each group, wherebysaid switch may be selectively positioned 'in accordance with saidoperated registering devices.

11. In a telephone exchange system, a selector switch, means forcontrolling the advance of said switch, a plurality of groups ot'testing terminals, each of said groups being divided into a plurality ofsubgroups, wipers associated with said switch for simultaneouslyconnecting terminals in all of said groups with said controlling means,a source ot testing potential normally connected to all of saidterminals and means comp-rising registering` devices for selectivelydisconnecting said potential from the terminals of any sub-grouprof oneof said groups and from lany terminal of one of the sub-groups ofanother ot said groups, whereby said switch may be positioned inaccordance with said operated registering devices.

12. In a telephone exchange system, switching mechanism, a plurality 'ofregistering devices for recording the designations of desired lines,means controlled by said registering devices for controlling saidswitching mechanism to extend connections to said desired lines, andmeans comprising a cross-connecting rack associated with saidregistering devices and said control means adapted to be readily changedto modify the control of -said switching mechanism by said registeringdevices.

13. In a telephone exchange system, switching mechanism, a plurality ofregistering devices for recording the designations of desired lines,means controlled by said registering devices for controlling saidswitching mechanism to extend connections to said desired lines, and lacross connecting rack interposed between said registering devices andsaid control means 'having jumper connections adapted to be readilychanged to modify the control of said switching mechanism by saidregistering Y devices.

14. In a telephone exchange system, switching mechanism, a plurality ofregistering devices for recording the design-ations of desired lines, atranslator switch, means for setting said switch into a position jointlydetermined by said'registeringdevices, means 'for controlling saidswitching mechanism to extend connections to said desired lines andmeans interposed between the bank terminals of said switch and saidcontrol means adapted to be readily changed to modify the control ofsaid switching mechanism by said registering devices.

15. In a telephone exchange system, switching mechanism, a plurality ofregistering devices for recording the designations of desired lines, atranslator switch, means for setting said switch into a position jointlydetermined by said registering devices, means for controlling saidswitching mechanism to extend connections to said desired lines, and across connecting rack interposed between the bank terminals of saidswitch and said control means adapted to be readily changed to .modifythe control of said switching mechanism by said registering devices.

In witness whereof, I hereunto subscribe my name this 21st day ofAugust, A. D., 1919.

ALBEN E. LUNDELL.

